An acoustic/ultrasonic detection system can detect, for example, an object concealed under the clothing of a subject. The system includes a signal generator configured to output an electrical signal. An acoustic/ultrasonic transducer can be configured to convert the electrical signal into an acoustic/ultrasonic signal, transmit the acoustic/ultrasonic signal, receive a reflected acoustic/ultrasonic signal from an object in the target area and convert the reflected acoustic/ultrasonic signal into a received electrical signal. The transducer is at least one of an air-coupled transducer and an electro-magnetic acoustic transducer. The system can also include an acoustic/ultrasonic antenna aperture operatively connected to the transducer and configured to focus the transmitted acoustic/ultrasonic signal to create a narrow beam in the target area, a processor configured to extract object information from the received electrical signal and an object indication device to provide an indication of a detected object based on the extracted object information.